Dating to the Norman invasion of Ireland, the town's walls were first laid-out in the 13th century, with some sections of these defensive fortifications surviving today.

[6] While the low hill, on which the town stands, may have been the location of a pre-Norman church, the first evidence of significant settlement dates from 1201, when a Norman lord, likely William de Braose, settled here.

Under this constitution, the town's people (burgesses) had fixed annual rents, access to a court, and defined fines for certain offences.

The first reference to the walling of Fethard dates to 1292 when the king allowed levies to be applied (over seven years) on items sold in the town, with the collected funds allocated to "the inclosing of their vill and the greater security of Ireland".

[6] The town received a royal charter from Edward VI in 1552–3, allowing it a corporation in perpetuity, composed of one Sovereign, one Provost, Burgesses and inhabitants.

[7] John Everard, a lawyer and member of a local landed family, served the Butler clan and Earl of Ormond.

[7] By the 18th century, some parts of the town were in a state of decay, with the corporation's books for 1718 noting that 56 people had houses with dangerous chimneys.

The new landowner, Mr Barton (a wine merchant from Bordeaux), replaced the old Everard mansion with a new house, which in turn became a military barracks early in the 19th century.

[12] The town is also known in the thoroughbred horse racing industry as the home of Coolmore Stud and of the stables of Michael "Mouse" Morris.

A parade runs through the main street that culminates in Valley Park centred on the River Clashawley, next to the town's medieval walls.